1. Field of the Invention
The present invention relates to an output-attached measuring instrument. More specifically, it relates to an output-attached measuring instrument capable of outputting measurement data measured by a measuring instrument to the outside.
2. Description of Related Art
Conventionally, small measuring instruments (hand tool) manually held by an operator for measuring a workpiece, such as a caliper and a micrometer, have been widely used.
Among the hand tools, a caliper has a main scale, a slider capable of moving in longitudinal direction of the main scale, a displacement sensor for detecting the displacement of the slider as an electric signal and a digital display for digitally displaying the displacement of the slider detected by the displacement sensor.
Some of the calipers (output-attached caliper) are capable of outputting the displacement of the slider, i.e. a measurement signal, detected by the displacement sensor to the outside.
Conventionally, in order to manufacture the output-attached caliper, a connector connected to the displacement sensor and having an exposed electrode is formed on a part of the slider, and another connector fitted to the connector on the slider and having an exposed electrode connected to the electrode is attached to a tip end of a connection cable connected to an external device such as data processor.
In use, when the connector provided at the tip end of the connection cable is fitted to the connector formed on the slider, the electrodes provided on the connectors are mutually connected, so that the measurement signal obtained by the caliper is transmitted to an external device such as a data processor through the connection cable, where the measurement signal is processed.
However, according to such conventional output-attached measuring instrument, following disadvantage accompanied.
First, since the electrode is exposed on the connector, the use of the output-attached caliper under an undesirable condition where water, oil, and dust easily invades therein, was very difficult for fear of the invasion of the water, oil and dust etc.
Secondly, when the caliper is used under such undesirable condition, the fitted portion has to be covered by a rubber packing etc to prevent invasion of the foreign body, so that the structure of the caliper becomes complicated.
An object of the present invention is to provide an output-attached measuring instrument capable of solving the conventional problems and capable of using under a severe undesirable condition without employing complicated structure.
An output-attached measuring instrument according to an aspect of the present invention includes: a measuring instrument body having a sensor, a circuit board for processing a measurement signal from the sensor as a measurement data, an output electrode for outputting the measurement data from the circuit board, and a connector hole in communication with the output electrode and opening to an outer surface; and a connection cable having a connector capable of attaching to and detaching from the connector hole for transmitting the measurement data obtained by the measuring instrument body to an external device, the connector having a projection capable of being plugged to and unplugged from the connector hole and a connector terminal exposed on a surface thereof, where an elastic connector having am electro-conductive portion for electrically connecting the connector terminal and the output electrode is accommodated in a space of the connector hole of the measuring instrument body, and where the elastic connector shuts the connector hole when the projection is unplugged from the connector hole and electrically connects the connector terminal and the output electrode through the electro-conductive portion when the projection is plugged into the connector hole.
Alternatively, an output-attached measuring instrument according to the present invention includes: a measuring instrument body having a sensor, a circuit board for processing a measurement signal from the sensor as a measurement data, an output electrode for outputting the measurement data from the circuit board, and a connector hole in communication with the output electrode and opening to an outer surface, the measuring instrument body capable of transmitting the measurement data to an external device using a connection cable having a connector with a connector terminal exposed on a surface thereof and being capable of attaching to and detaching from the connector hole, the connector having a projection capable of being plugged to and unplugged from the connector hole, where an elastic connector having am electro-conductive portion for electrically connecting the connector terminal and the output electrode is accommodated in a space of the connector hole of the measuring instrument body, and where the elastic connector shuts the connector hole when the projection is unplugged from the connector hole and electrically connects the connector terminal and the output electrode through the electro-conductive portion when the projection is plugged into the connector hole.
According to the above arrangement, the measurement signal measured by the sensor of the measuring instrument body is processed by the circuit board as a measurement data to be sent to the output electrode.
While the projection is inserted into the connector hole, the connector terminal is in contact with the surface of the elastic connector and the output electrode and the connector terminal are electrically conducted by the electro-conductive portion provided on the outer surface of the elastic connector, so that the measurement data obtained by the measuring instrument body can be transmitted to an external device through the connection cable.
When the projection of the connector is unplugged from the connector hole, the connector hole is shut by the elastic connector. In other words, the outside and the output electrode are isolated. Accordingly, the invasion of the water, dust etc. from the outside through the connector hole into the output electrode and the circuit board can be prevented, and the situation where the data cannot be transmitted can be avoided, thus enabling to use the output-attached measuring instrument under severe environment.
Further, since the connector terminal and the output electrode are in contact through the elastic connector, secure contact can be obtained by the elastic contact pressure of the elastic connector and the connector terminal and the output electrode are less likely to be damaged even after repeated plugging and unplugging of the connector as compared to bringing the connector terminal and the output electrode into direct contact.
In the present invention, the connector hole may preferably include: a perpendicular channel perpendicular to the circuit board; and an opening channel bent from an end of the perpendicular channel and opening toward the outer surface of the measuring instrument body, where the elastic connector may preferably be provided in the perpendicular channel, the elastic connector shutting the opening channel when the projection is unplugged from the connector hole and electrically connecting the connector terminal and the output electrode while being elastically deformed when the projection is inserted into the connector hole.
Specifically, when the connector hole in communication with the outside is linearly provided from the output electrode, the output electrode is situated on a stress line from the projection when the projection is inserted into the connector hole. As a result, when the projection is inserted into the connector hole, the stress equal to the stress applied to the elastic connector by the projection is applied to the output electrode, thereby increasing the load applied on the output electrode.
On the other hand, according to the present invention, since the connector hole is bent at the border between the perpendicular channel and the opening channel and the elastic connector is arranged to shut the opening inside the perpendicular channel, the stress applied on the elastic connector by the projection is not directly applied on the output electrode, thereby reducing the load applied on the output electrode.
Further, an elastic body has characteristics of elastically deforming and expanding in a direction orthogonal with a stress direction. In other words, when the projection is inserted from the opening channel, the elastic connector is elastically deformed and expanded along the perpendicular channel, the elastic connector can be in contact with the output electrode at an appropriate pressure by the elastic deformation.
In the present invention, an elastic sealing member may preferably be provided along the periphery of the opening channel on the outer surface of the measuring instrument body, and the elastic sealing member may preferably seal the gap between the measuring instrument body and the connector while being compressed when the projection of the connector is inserted into the opening channel.
Since the elastic connector is elastically deformed when the projection of the connector is inserted into the connector hole, the connector hole is not shut by the elastic connector.
However, since the elastic sealing member is provided along the periphery of the opening, the connector hole is isolated from the outside by the close contact between the elastic sealing member and the connector when the connector is inserted. Accordingly, invasion of water, oil, dust etc. from the connector hole into the inside of the measuring instrument can be prevented, thus enabling use of the measuring instrument under severe environment.
In the present invention, a plurality of the electro-conductive portions connecting a surface opposing the opening channel and a surface opposing the output electrode may preferably be provided to the elastic connector sandwiching a non-electro-conductive portion therebetween.
According to the above arrangement, when the elastic connector touches the connector terminal and the output electrode from the surface facing the opening channel and the surface facing the perpendicular channel, the output electrode and the connecter terminal are electrically connected by the electro-conductive portion of the elastic connector.
At this time, since the elastic connector has a plurality of the elastic connectors sandwiching the non-electro-conductive portion, a plurality of data can be simultaneously transmitted from the output electrode to the connector terminal.
In the present invention, the sensor may preferably be a caliper having a main scale with a first measurement jaw provided at an end in the longitudinal direction and a slider movable in the longitudinal direction of the main scale and having a second measurement jaw to be in contact with the workpiece together with the first measurement jaw, and the circuit board, the output electrode and the connector hole may preferably be provided on the slider.
According to the above arrangement, when the measurement jaws provided on the main scale and the slider of the caliper are moved to be in contact with a target portion of a workpiece, the displacement of the slider is processed into signal as a measurement data to be transmitted to the output electrode.
When the projection of the connector terminal is inserted into the connector hole, the connector terminal and the output electrode are electrically connected through the electro-conductive portion of the elastic connector, the measurement data can be transmitted from the output electrode to the connector terminal.
When the projection of the connector is not inserted into the connector hole, the connector hole is shut by the elastic connector to isolate the outside from the output electrode. Accordingly, the invasion of the water, dust etc. from the outside through the connector hole into the output electrode and the circuit board can be prevented, and the situation where the data cannot be transmitted can be avoided, thus enabling to use the output-attached measuring instrument under severe environment.
Further, since the connector terminal and the output electrode are in contact through the elastic connector, secure contact can be obtained by the elastic contact pressure of the elastic connector and the connector terminal and the output electrode are less likely to be damaged even after repeated plugging and unplugging of the connector as compared to bringing the connector terminal and the output electrode into direct contact.